Bearings

Sep 29, 2026
Sep 29, 2026
GAME THEORY · a theorem published by Moshe Tennenholtz in 2004

Programs That Read Rivals' Code Can Learn To Cooperate

Setup. In the classic prisoner's dilemma, both players do better by betraying each other, even though both would gain more by cooperating, because neither can trust a promise. Program equilibrium, a concept introduced by Moshe Tennenholtz in 2004, asks what happens when players do not pick an action directly but instead submit a computer program that can read the opponent's source code and decide for them.

The finding. One simple program, CliqueBot, cooperates only if the opponent's code matches its own exactly, a plan that collapses if either side edits even a single character. A sturdier program, FairBot, instead tries to prove the opponent will cooperate before it does, using a result from mathematical logic called Löb's theorem, it can be shown that when both players submit this program, they cooperate against each other. A folk theorem shows any payoff at least as good as a player's guaranteed minimum can be reached this way.

Where it stands. This is a proven mathematical result, not an experiment, and it assumes programs can read each other's exact code, a condition ordinary negotiation never meets. It has gained new relevance now that AI agents increasingly transact with some visibility into each other's code or weights.

Moshe Tennenholtz · Wikipedia · 2004 ↗
ANCIENT HISTORY · a magazine essay built on the archaeological and isotopic record · Sep 2026

Cheap Iron, Not Bronze, Explains Empires' Fall

Setup. Around 1200 BC the great Bronze Age empires of the eastern Mediterranean, Egypt, the Hittites, Assyria, Mycenaean Greece, collapsed within a few generations. Historians usually blame drought, invaders and revolt. None of that explains the odder fact: for centuries afterward, nothing of comparable scale rose to replace them.

The argument. Patrick Fitzsimmons argues the empires never returned because the material basis of military power changed. Bronze needed tin, found only in a handful of distant deposits in modern Afghanistan, Cornwall and Iberia, so only large, organized states could reliably arm big forces. Iron ore, by contrast, is the fourth most abundant element in Earth's crust and sits visibly near the surface almost everywhere. Because iron could be produced locally, imperial centers no longer had such a strong advantage over their subject peoples. Skeletal evidence shows violence rose after iron spread, even as large empires stayed absent.

Where it stands. This is a magazine essay synthesizing archaeology and isotope-tracing research, not one new study, and historians still debate what triggered the initial 1200 BC collapse. The iron-democratization mechanism is a well evidenced explanation for why empires stayed fragmented afterward, a separate and more testable question than what caused the collapse itself.

Patrick Fitzsimmons · Works in Progress · Sep 2026 ↗
CORPORATE FINANCE · a theorem published by Franco Modigliani and Merton Miller in 1958

Debt Or Equity, A Firm's Value Stays The Same

Setup. A company can raise money by selling shares, borrowing, or some mix of the two. Business intuition treats this as a real choice with real consequences for what the company is worth, and lenders, investors and executives spend enormous effort arguing over the ideal mix of debt and equity.

The finding. Franco Modigliani and Merton Miller showed in 1958 that, in a market with no taxes, no bankruptcy costs and no informational advantage for insiders, the enterprise value of a firm is unaffected by how that firm is financed. The proof rests on arbitrage: if a levered and unlevered version of the same firm ever traded at different prices, investors could borrow or lend on their own account to capture the difference, pushing the two prices back together. Both economists later won a Nobel Prize partly for this result.

Where it stands. This is a proven theorem, not an empirical claim, and its own assumptions name where it breaks down. Once interest payments become tax-deductible, added debt raises firm value, which is exactly the boundary condition that makes real capital structure decisions matter in practice.

Franco Modigliani and Merton Miller · Wikipedia · 1958 ↗
EVOLUTIONARY GENETICS · magazine essay built on peer-reviewed genome studies · Sep 2026

A Stray Gene Insertion Turned Moths Black In 1819

Setup. Nearly half of the human genome consists of transposons, DNA sequences that can cut or copy themselves out of one spot in a genome and paste themselves somewhere else. Long dismissed as genetic junk or viral leftovers, they are now understood to sometimes drive real evolutionary change, not just accumulate as clutter.

The finding. England's peppered moths turned from speckled white to solid black after coal pollution darkened tree bark in the Industrial Revolution, a textbook case of natural selection. It took until 2016 for geneticists to find the actual mechanism. A transposon, absent in the white-winged moths, had been inserted into the beginning of this gene in nearly all the black moths and had led, through an unknown mechanism, to the production of dark-colored wings. The researchers dated the insertion to 1819, just as pollution began reshaping the moths' habitat.

Where it stands. This is one well-documented case built on a peer-reviewed 2016 genome study, not proof that transposons usually drive adaptation this cleanly. Researchers still debate how the insertion actually changes wing color at the molecular level. The broader pattern, that transposons have shaped eyes, immune systems and even the placenta across many species, rests on a wider but less tightly dated body of evidence.

Jake Buehler · Quanta Magazine · Sep 2026 ↗
BEHAVIORAL GAME THEORY · a solution concept introduced by Richard McKelvey and Thomas Palfrey

Game Theory That Expects Players To Make Mistakes

Setup. Classical game theory, built around the Nash equilibrium, assumes every player always picks their single best move given what everyone else is doing. Real people do not play that cleanly. They make errors, but the errors are not random noise, they cluster around the choices that are cheap to get wrong.

The finding. Richard McKelvey and Thomas Palfrey built an alternative called quantal response equilibrium, where a strategy's probability of being chosen rises with its payoff rather than being all-or-nothing. A parameter tunes how sharp this gets: near zero, players choose at random, and as it grows large, play converges back to Nash equilibrium. A large-scale analysis of the American television game show The Price Is Right, for example, shows that contestants behavior in the so-called Showcase Showdown, a sequential game of perfect information, can be well explained by an agent quantal response equilibrium (AQRE) model.

Where it stands. The model fits laboratory and real high-stakes data better than pure Nash equilibrium across many published tests. Its own critics have shown it is not falsifiable in general games without extra restrictions, meaning its flexibility can make almost any behavior look consistent with it after the fact.

Richard McKelvey and Thomas Palfrey · Wikipedia ↗
Sep 28, 2026
PSYCHOLOGY · a 2002 study, contested in 2011, reconfirmed with census data in 2015

People Gravitate Toward Anything That Resembles Their Own Name

Setup. People like to feel good about themselves. Psychologists Brett Pelham, Matthew Mirenberg, and John Jones argued in 2002 that this quietly shapes choices unrelated to self-image, an effect they called implicit egotism. It was used to explain nominative determinism, the idea that people gravitate toward jobs that fit their own names.

The finding. Uri Simonsohn attacked the theory in 2011, reanalyzing the same data and calling the name-job correlations "spurious." Pelham and Mauricio Carvallo answered in 2015 with three independent censuses, 1880 and 1940 United States and 1911 England, controlling for gender, ethnicity, and education. They found people disproportionately worked in eleven trades that matched their own surnames: baker, barber, butcher, butler, carpenter, farmer, foreman, mason, miner, painter, and porter. The same data showed people tended to marry partners sharing their birthday number or birth month.

Where it stands. This is a live replication fight, not a settled finding. Simonsohn's critique was serious and forced better controls. Pelham and Carvallo's reply used three independent population datasets, a stronger design than the original lab study. The surname pattern now has real population-scale support. The claimed mechanism, an unconscious pull toward the self, is still inferred from the pattern rather than measured directly.

Pelham, Mirenberg and Jones · Wikipedia, 2002 ↗
HISTORIOGRAPHY · a 1990 thesis contested by historians of medicine since 2003

A Historian's Story About Sex Difference Doesn't Hold Up

Setup. In 1990 historian Thomas Laqueur published Making Sex, arguing Western medicine had for centuries treated female anatomy as an inverted, inferior copy of male anatomy, a "one-sex model," before flipping around the 18th century to a "two-sex model" that treated the sexes as opposite. He read ancient physicians like Galen as believing the vagina was literally an internal penis, the uterus a scrotum, differing only by a lack of bodily heat.

The argument. Laqueur claimed the switch was political, not scientific: Enlightenment thinkers needed to ground the exclusion of women from public life in biology rather than custom, once the French Revolution made appeals to custom unstable.

Where it stands. The thesis has not survived contact with specialists. Michael Stolberg's 2003 article showed explicit anatomical sex difference in print by the early 17th century, at least 200 years before Laqueur's claimed turning point. Katharine Park and Robert Nye argued Laqueur misread Galen, mistaking an explanatory analogy for a claim of literal sameness. Helen King's 2013 book found both models coexisting since antiquity, and historian Monica Green called in 2018 for the field to abandon the framework entirely.

Thomas Laqueur · Making Sex: Body and Gender from the Greeks to Freud, 1990 ↗
ARMS CONTROL · analysis of the nuclear nonproliferation record · Sep 2026

Nuclear Nonproliferation Worked Through Coercion, Not Just Treaties

Setup. AI executives now compare their technology to nuclear weapons: Dario Amodei calls powerful models "weaponizable nuclear materials," and Sam Altman points to the International Atomic Energy Agency as a template. Scholars Christopher David LaRoche and Ankit Panda tested whether the history behind 81 years without nuclear war actually supports copying its methods for AI.

The argument. The record is messier than the analogy assumes. South Korea and Taiwan gave up weapons programs under direct US coercion, not treaty design; Israel bombed Iraqi and Syrian reactors rather than rely on inspections. When states were determined to develop nuclear weapons and could withstand outside pressure, the nonproliferation regime had little power to stop them. India, Israel, North Korea, and Pakistan all managed to build the bomb. AI is also harder to trace: uranium and plutonium are scarce and physically constrained, while a trained model's weights can be copied and run anywhere.

Where it stands. This is an argument from documented history, not a new finding, by authors who are nuclear-policy specialists rather than neutral observers of AI. That coercion, not treaty design, did most of the real work is well supported by the named cases. The weaker claim is predictive: that AI's traceability problem makes a nuclear-style regime unworkable is a reasoned inference from the technology's structure, not yet tested.

Christopher David LaRoche and Ankit Panda · Foreign Affairs · Sep 2026 ↗
SOCIAL PSYCHOLOGY · a finding replicated across six decades since 1961

Groups Don't Average Opinions, They Amplify Them

Setup. In 1961 MIT student James Stoner found something odd: groups made riskier decisions than the average of what their members chose alone, later named the "risky shift." Researchers had expected discussion to average views toward the middle, not push them further out.

The finding. By the late 1960s the pattern was generalized to group polarization: discussion pushes a group's position toward whatever its members already leaned toward, whether the topic is risk or politics. A 1979 study by Charles Lord, Lee Ross, and Mark Lepper showed the same logic applies to evidence itself. Supporters and opponents of capital punishment read identical mixed research, then rated whichever study matched their own view as better conducted. Whichever position they held initially, people tended to hold that position more strongly after reading research that supported it.

Where it stands. Group polarization has replicated across juries, online platforms, and labs for six decades, under two explanations: people shift toward the group's admired position, or they hear mostly one-sided arguments during discussion. Evidence supports both, likely operating together. The 1979 capital-punishment study had an acknowledged methodological flaw, but the broader polarization effect it dramatized has held up well.

James Stoner · Wikipedia, 1961 ↗
BEHAVIORAL ECONOMICS · synthesis of named studies since Asch's 1951 experiments

Copying The Crowd Can Be The Rational Choice

Setup. Herd behavior is usually treated as a failure of reasoning, people copying a crowd instead of thinking for themselves. Economists distinguish this from rational herding, where copying others is the most sensible response to real uncertainty, not a lapse in judgment.

The mechanism. When people believe others hold useful private information, copying the majority becomes a reasonable shortcut. This logic is formalised in models of information cascades, in which each person rationally ignores their own private signal because the weight of prior public choices is more informative. The result is that collectively irrational outcomes, such as financial bubbles or fads, can emerge from individually rational, well-intentioned reasoning. Two biases shape who gets copied: prestige bias favors people who look skilled regardless of relevance, and success bias credits a behavior for an outcome it may not have caused.

Where it stands. The core logic is well established theoretically and traces to real experiments like Solomon Asch's 1951 conformity studies. The harder question, how much real-world herding in markets or medicine is genuinely rational rather than emotional contagion, is less settled. The article itself notes the finance literature leans on price and investment data because it is easy to get, not because it best tests the theory.

unknown · Wikipedia, 1951 ↗
Sep 27, 2026
ANTHROPOLOGY · foundational 1925 sociological essay · 1925

Gift Economies Refute The Idea Trade Came First

Setup. Classical economics assumes trade began with individuals bartering out of self-interest, and that gift-giving came later as a courtesy layered on top. In 1925 the French sociologist Marcel Mauss, working from other researchers' field reports rather than his own, tested that assumption against real archaic societies.

The argument. Mauss found that exchange in these societies was never a one-off transaction between individuals. Early exchange systems center around the obligations to give, to receive, and, most importantly, to reciprocate, and the exchange runs between whole groups, not persons. A gift built a debt an entire clan had to answer, binding economics, law and religion into one cycle Mauss called a total social fact.

Where it stands. Mauss never did fieldwork himself. He synthesized reports from Malinowski's Trobriand Islands work, Boas's Pacific Northwest potlatch, and Radcliffe-Brown's Andaman Islanders, so the argument rests on secondhand ethnography, not a controlled study. Its central claim, that reciprocal obligation predates and outranks market exchange, still anchors the modern study of gift economies and shaped Lévi-Strauss and Graeber after him.

Marcel Mauss · The Gift, 1925 ↗
EVOLUTIONARY BIOLOGY · comparative-oncology studies across species · 1977

Bigger Animals Get Less Cancer, Not More

Setup. Cancer starts when a dividing cell picks up the wrong mutation. More cells dividing more times should mean more chances for that to happen, so bigger, longer-lived animals should get more cancer than small ones. In 1977 epidemiologist Richard Peto noticed the data said the opposite.

The finding. The incidence of cancer in humans is much higher than the incidence of cancer in whales, despite a whale having about 1000 times more cells than a human. A 2015 San Diego Zoo survey of 36 mammal species, from a 51-gram mouse to a 4,800-kilogram elephant, found no link between body size and cancer rate. Elephants carry 20 copies of the tumor-suppressor gene TP53 to a human's one, and their larger cells also divide more slowly, cutting the chances a mutation takes hold.

Where it stands. The pattern holds only across species. Within one species, including humans, taller people do get more cancer, confirmed in studies of British civil servants and over a million British women. The paradox is specifically cross-species, and the TP53 and cell-division evidence for why large animals evolved extra protection is now well corroborated.

Richard Peto · Peto's paradox, 1977 ↗
LABOR ECONOMICS · a philosopher's 1966 concept, named and tested by an economist in 2014 · 1966

Tacit Knowledge Explains Why Automation Stalls

Setup. Programming a task requires spelling it out in full, but most people cannot fully explain how they recognize a face or drive through traffic, they just do it. Philosopher Michael Polanyi identified this gap in 1966. Economist David Autor named it Polanyi's paradox in 2014.

The argument. Polanyi's paradox is mainly to explain the cognitive phenomenon that there exist many tasks which we, human beings, understand intuitively how to perform but cannot verbalize their rules or procedures. Autor linked this to occupational polarization: routine, codifiable middle-skill jobs got automated away, while both abstract high-skill jobs and physical low-skill jobs, which lean on tacit judgment, proved stubborn and grew as a share of employment instead.

Where it stands. Occupational polarization itself is documented, not just Autor's framing of its cause. The paradox is also actively contested: machine-learning systems now learn tacit patterns straight from data rather than needing a programmer to state them explicitly, and AlphaGo's 2016 win over Lee Sedol is the standard counterexample cited against the paradox holding indefinitely.

David Autor · Polanyi's paradox, 2014 ↗
HISTORIOGRAPHY · a historical thesis traced through three theorists and one police career · 1950

Colonial Policing Tactics Return Home To Local Police

Setup. Empires develop surveillance, forced labor and violent policing to control colonies far from home. In 1950 Aimé Césaire argued these methods do not stay in the colonies. Hannah Arendt made the same case in 1951, and Michel Foucault repeated it in a 1976 lecture, each calling it a boomerang effect.

The argument. The theory holds that a colonial power eventually turns its own colonial techniques on its own citizens. The clearest documented case is policing: Go writes that August Vollmer, first police chief of Berkeley, California, often referred to as "the father of modern policing", introduced innovations which were "taken from his colonial counter-insurgency experience in the Philippines." Sociologist Julian Go calls this transfer imperial feedback, a named mechanism rather than a loose analogy.

Where it stands. Vollmer's career is a documented case, not a metaphor. The direction of causation is genuinely contested: political scientist Stuart Schrader argues domestic racialized policing shaped American empire first, rather than the reverse Césaire described, so historians differ on which flowed from which.

Julian Go · Imperial boomerang concept, 1950 ↗
SOCIAL PSYCHOLOGY · peer-reviewed study, five linked experiments · 2001

You Believe You Know Others Better Than They Know You

Setup. People routinely judge how well they know a friend, a rival, or a rival group, and how well that friend or rival knows them back. Psychologists Emily Pronin, Justin Kruger, Kenneth Savitsky and Lee Ross ran five studies in 2001 testing this in pairs, including roommates.

The finding. The rating was never balanced. We believe we know our roommates better than they know us. We know ourselves better than our roommates know themselves. People treat their own private thoughts and off-the-cuff answers as revealing of a true self, but read someone else's identical off-the-cuff answer as shallow. The same asymmetry appeared between social groups, each side rating its own understanding of the other as deeper than the reverse.

Where it stands. The five-study design is solid within its own paradigm, but it is one research group's 2001 result, from before psychology's replication reckoning, and it has not been retested at the scale of the field's better-known biases. Treat it as a documented pattern, not yet a finding with the standing of a heavily replicated effect.

Pronin, Kruger, Savitsky and Ross · Journal of Personality and Social Psychology, 2001 ↗
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